1. Field of the Invention
The present invention relates to a register for use with a heating-ventilation and air-conditioning (HVAC) unit, more particularly to one with a manually adjustable toggle-joint mechanism to easily and precisely control airflow therethrough.
2. Description of the Related Art
It is known in the art that a central heating ventilating and air conditioning (HVAC) system incorporates a plurality of registers. The heating/conditioning air supplied by the HVAC unit is delivered into one or more zones of a house or a building through a plurality of air ducts by means of air pumps and into the zones via the plurality of registers installed at the ends of the air ducts. Two types of registers are commonly used: an air vent providing a constant amount of air flow, and an adjustable register providing a varied amount of air flow. Generally, in case that temperature control for individual zones is not required, the air supplied by the HVAC unit is constantly delivered into the zones via air vents and all zones are supplied with heating/conditioning air. In case the temperature control for individual zones is required, adjustable air registers are needed to meet this demand. When a zone is not occupied by people and thus heating/conditioning air is not needed, the adjustable register(s) installed therein can be shut off to block air flow so as to save energy. However, the presently available registers, though being capable of minimizing air flow therethrough, fail to effectively and completely block the same. As such, the goal of energy conservation is not satisfactorily realized.
FIGS. 1 to 3 illustrate a conventional adjustable register. The adjustable register 1 includes a rectangular hollow frame 2, a plurality of parallel slats 4, and a slat-adjusting assembly 6 including a connecting linkage 8 and an operating lever 10. The front end of the frame 2 is provided with a louvered structure 14 having a plurality of air passages 16 through which the air heating/conditioning air supplied by the HVAC unit (not shown in the drawings) can be delivered into a zone where the register 1 is installed. As clearly shown in FIG. 2, the frame 2 has two side mounting walls 18 that extend rearwardly. Each of the parallel slats 4 (three slats 4 are shown in the drawings) has two opposing pivoting ends pivotally mounted on the side mounting walls 18, respectively, at a first pivot portion 19. Aside from being pivotally connected to the respective one of the side mounting walls 18, one of the pivoting ends of each of the slats 4 is also pivotally mounted on the connecting linkage 8 of the slat-adjusting assembly 6 at a second pivot portion 20. The second pivot portion 20 of each of the slats 4 is spaced apart from the first pivot portion 19. One end of the operating lever 10 adjacent to the connecting linkage 8 is formed with a guiding slot 22, where the second pivot portion 20 of the middle one of the slats 4 is located and movably guided. The operating lever 10 has a distal operating end 28 remote from the guiding slot 22, which extends forwardly through a slot 24 formed in the frame 2 and parallel to the side mounting walls 18. The operating lever 10 is pivotally mounted on one of the side mounting walls 18 adjacent to the connecting linkage 8 at a pivot center 26 which is located between the operating end 28 and the guiding slot 22. The slot 24 is of sufficient length so that the operating end 28 of the operating lever 10 can be operated to move upward and downward within a predetermined range.
As the operating lever 10 pivots, the second pivot portion 20 of the middle one of the slats 4 is driven to move along the length of the guiding slot 22. Such a movement results in the movement of the connecting linkage 8, which in turn causes the slats 4 connected thereto to pivot about a pivot axis extending through the two opposing first pivot portions 19 of each of the slats 4. As a result, the slats 4 are pivoted between a closed position where the slats 4 overlap the longitudinal edges of the adjacent slats 4 or the frame 2 to cover the air passages 16, and an open position where the air passages 16 are not blocked to allow air flow therethrough.
The above-mentioned construction, however, is functionally incomplete in some aspects. For example, the blocking effect is not satisfactorily achieved. When in the closed position, the slats 4 fail to contact tightly the frame 2 or the adjacent slats 4, thereby allowing air to easily leak through the clearances between adjacent two of the slats 4 and between the lowermost slat 4 and the frame 2, as indicated by (A) in FIG. 3. Besides, the slot 24 where the operating lever 10 extends also serves as an air leaking passage, as indicated by (B) in FIG. 3. Therefore, air-tight effect is unlikely to be achieved in the conventional register 1, and energy is wasted.